Gradient measuring apparatus



FIG. 1 is a perspective view of a holder for a ball leveler with mount;

FIG. 2 is a front view thereof;

FIG. 3 is a side view thereof;

FIG. 4 is a top view thereof; and,

FIG. 5 is a bottom view thereof.

Dashed lines are to show environment and do not form a part of the claimed invention. 

CLAIM I claim the ornamental design for gradient measuring apparatus, as shown and described. 